Voice - In the breeding season, the male Pied-billed Grebe often calls all day long, even at night, its voice ringing across the marsh. Its voice sounds like a series of hollow "cow-cow-cow's" repeated and increasing in speed, usually ending with "cow-ah-cow-ah". The entire repertoire might sound like "oo-o- o-ah-ah-eh-i-ay-eee- eeto-eeto- eeto-eeto ayto ayto ayto yto ah ih oh oo oo oo". It also makes a "whinny" sound and utters a single mellow note.